Clamping heads, generally, have been known in the prior art. For example, Federal Republic of Germany patent document No. 1,574,438 illustrates a clamping head as being a relatively long generally cylindrical assembly formed of a plurality of relatively long arcuate-like pipe-like segments. In transverse cross-section, as in FIG. 2 of said patent document, the outer-most periphery of each of such segments lies in what may be considered a cylindrical configuration and forms a sector thereof. The circumference or outer periphery of each of such segments is provided with a longitudinally extending serration. Except for a very short bevel which facilitates the introduction of the clamping head into the winding tube 11, the teeth of the serration have a constant cross-section extending for the full length thereof between the free end of the clamping head and the associated collar 31 (FIG. 1 of said patent document). Upon expansion of the cylindrical assembly, after its introduction or insertion into the winding tube, the arcuate or cylindrical segments are pressed or forced against the inner cylindrical surface of the core or winding tube. Consequently, the winding tube, of said patent document, is supported only by the tips of the teeth comprising the serration. Further, if any penetration into the body of the winding tube by such outer tips of the teeth occurs, neither the depth nor uniformity of such penetration is in any way controlled or gauged and therefore the axis of the winding tube becomes misaligned to the axis of rotation of the clamping head. Such a disclosed clamping head cannot fulfill the operating requirements that exist in connection with modern winding machines as for example disclosed in Federal Republic of Germany Letters Patent No. 3,243,994.
Presently, in order to be acceptable, the structural length of the clamping head used at the ends of the winding tubes must be short so that the axial movement of the clamping head, for introduction into and extraction from the winding tube, will also be short. Such short movement, of course, is an important factor in the overall time required for changing as from a full to an empty winding tube as well as in determining the maximum width or axial length of the winding tube which may be employed in a particular machine. Further, the clamping head must be able to support the relatively great weight of the roll being formed on the winding tube without destruction of the winding tube when, for example, to influence or control the winding harness, the line pressure of the wound roll on the roll-carrying cylinders of the machine is reduced. For acceptable products, there must be no deflection of the roll to be wound. Also, for proper operation, there can be no relative rotation as between the clamping head and the winding tube especially if the length of material wound onto or off the winding tube is to be determined, as by related automatic sensing means directly or indirectly sensing the rotation and revolutions of the clamping head. In such arrangements, the assured rotation of the clamping head in unison with the winding tube is indispensible for the exact determination of the length of the web material to be wound or unwound as well as for controlling the winding hardness of the web material.
The invention as herein disclosed is primarily directed to overcoming the aforestated problems of the prior art and to providing a clamping head having the desired characteristics and features as hereinbefore set forth.